search for: simplifyfdivinst

..., undef"/ is always folded to /"undef"/. Seems I am missing something important about floats here. The same applies to "fdiv". /"fdiv undef, undef"/ is not folded but /"div %X, undef"/ and /"div undef, %X"/ are folded to /"undef"/ (SimplifyFDivInst function in lib/Analysis/InstructionSimplify.cpp). Moreover, SimplifyFDivInst does not take into account whether signalling of SNaNs can be switched off or not - it always folds if one of the operands is /"undef"/. Another mysterious thing for me is folding of /"mul %X, undef&quo...

...y can be made non-signalling by poking > the processor AFAIK. > >> >> The same applies to "fdiv". >> /"fdiv undef, undef"/ is not folded but /"div %X, undef"/ and /"div >> undef, %X"/ >> are folded to /"undef"/ (SimplifyFDivInst function in >> lib/Analysis/InstructionSimplify.cpp). > > Here is the argument for "div %X, undef -> undef". The undef value > might be zero (div %X, 0), so lets choose it to be zero. That means > that the program has undefined behaviour at this point, and so we &...

...processor AFAIK. >>> >>>> >>>> The same applies to "fdiv". >>>> /"fdiv undef, undef"/ is not folded but /"div %X, undef"/ and /"div >>>> undef, %X"/ >>>> are folded to /"undef"/ (SimplifyFDivInst function in >>>> lib/Analysis/InstructionSimplify.cpp). >>> >>> Here is the argument for "div %X, undef -> undef". The undef value >>> might be >>> zero (div %X, 0), so lets choose it to be zero. That means that the >>> progra...